DE102020115182B4 - Device for melting and extruding a base material for a melt layer application, printer for 3D printing and method for regulating an application material flow of an extrusion device - Google Patents

Abstract

Device (101, 201) for melting and extruding a base material (119) for a melt layer application, the device comprising a feed unit (103, 203) for advancing the base material and a melted application material (121) with a feed force, a heating unit (111, 211 ) for melting the base material into the molten application material and an extruder nozzle (113, 213) for extruding the molten application material for the melt layer application, the device having a control device (117, 217) or the device is assigned a control device, and the device between the feed unit and the extruder nozzle (113, 213) has a force absorption unit (107, 207), characterized in that the device has a rigid holding unit (225), the extruder nozzle (113, 213) being arranged on the rigid holding unit, and the Device has a resilient lever arm (223), wherein the feed unit is arranged on the resilient lever arm, the resilient lever arm is connected to the rigid holding unit (225) and the force receiving unit is arranged on the resilient lever arm, so that a force directed opposite to the feed force by means can be detected by the force absorption unit and can be used by means of the control device to regulate a feed speed of the feed unit to set a constant application material flow.

Description

The invention relates to a device for melting and extruding a base material for a melt layer application, the device comprising a feed unit for advancing the base material and a melted application material with a feed force, a heating unit for melting the base material into the melted application material and an extruder nozzle for extruding the melted application material for the melt layer application, wherein the device has a control device or the device is assigned a control device. The invention further relates to a printer for 3D printing by means of melt layer application on a construction platform and a method for regulating an application material flow of an extrusion device.

In the private and industrial sectors, 3D printers are used to additively manufacture components by applying meltable raw material layer by layer. The additive manufacturing process, also called FFF (Fused Filament Fabrication), is an extrusion process in which thermoplastic starting material in wire form (also called filament) is usually fed to the extruder. Melting takes place in front of and/or in an extruder nozzle using a heating element (also called hot end). Here, the starting material is usually melted in a temperature range between 180 ° C and 300 ° C until it reaches the extrusion opening of the extruder nozzle and extruded through a usual nozzle cross section of 0.2 to 0.4 mm. By means of a feed unit, the solid, filament-shaped starting material and consequently also the starting material melted by the heating element are continuously advanced to the extrusion opening. The feed is usually controlled via a controller (control device), which often also sets the temperature of the heating element.

To build up the individual layers in 3D printing, the extruder nozzle is usually moved in a plane in the X and Y directions using a linear drive in order to cover the contours and surfaces with the melted starting material in layers.

A major influencing factor for the operational reliability of a 3D printer and the quality of the melt layer application is the constant volume of the melted application material. On the one hand, there is a requirement for a constant material flow and, on the other hand, the print head must move through the material at a speed proportional to the speed of the extruded application material Move the extruder nozzle to avoid material jamming during layer build-up. In practice, however, the material flow of the melted application material fluctuates and can lead to quality problems and scrap of the manufactured component.

The extrusion process in additive manufacturing is usually controlled using preset values, so that a preset feed rate is only carried out in an open mode of operation and a predetermined material flow is therefore used. An adjustment of the feed and thus the material flow often does not take place during the process, so that disturbances that occur during 3D printing are not taken into account and/or compensated for.

From the US 2019/0217546 A1 an additive manufacturing system with an extruder, motor and pressure sensor is known, in which the measured values of the pressure sensor are compared with predetermined values from a model using a controller and used to adjust the extrusion speed of the extruder. The disadvantage here is that real disturbances in the extrusion process, which are not taken into account in the model, are not adequately addressed and therefore the material flow cannot be optimally adjusted.

Furthermore, in the US 2019/0232566 A1 an extruder is described, in which a connection fluidly couples a pressure interface to an inner cavity of the extruder nozzle and a pressure sensor is arranged and configured in such a way as to measure a pressure inside the cavity of the extruder nozzle through the pressure interface and to provide feedback to the drive for correction of to give volume flow errors. However, an additional connection to the extruder nozzle is necessary here, which limits the mobility of the extruder nozzle and/or the print head in the installation space.

In the US 2019/0118258 A1 describes a method for maintaining an extruder nozzle of a 3D printer, in which the feed unit and the extruder nozzle are pivotally arranged on a crossbar in order to detect a blockage within the extruder channel or at the exit of the extruder nozzle by means of sensors arranged therebetween.

The US 2020/0139634 A1 discloses a 3D printer in which a compressive force sensor can be arranged at various positions, such as on an applicator, transport channel or on the extruder nozzle, in order to detect a force-related parameter before the filament is heated to its melting temperature.

In the US 2015/0224713 A1 discloses a liquefier for use in an extrusion-based additive manufacturing system in which a sensor is supported on a shoulder between the liquefier tube and the hollow liner to monitor the temperature, pressure or flow rate of the melt.

The object of the invention is to improve the state of the art.

The task is solved by a device for melting and extruding a base material for a melt layer application, the device having a feed unit for advancing the base material and a melted application material with a feed force, a heating unit for melting the base material into the melted application material and an extruder nozzle for extruding the molten application material for the melt layer application, wherein the device has a control device or the device is assigned a control device, and the device has a force receiving unit between the feed unit and the extruder nozzle, the device having a rigid holding unit, the extruder nozzle being arranged on the rigid holding unit is, and the device has a resilient lever arm, wherein the feed unit is arranged on the resilient lever arm, the resilient lever arm is connected to the rigid holding unit and the force-receiving unit is arranged on the resilient lever arm, so that a force directed opposite to the feed force is generated by means of the force-receiving unit can be detected and used by means of the control device to regulate a feed speed of the feed unit to set a constant application material flow.

A device is thus provided in which the material flow can be influenced directly and actively by means of the control device for regulating the feed of the base material and the melted application material. Above all, a constant material flow of the application material can be set promptly during extrusion based on the measured values of the force absorption unit by means of feedback via the control device.

It is particularly advantageous that the force absorption unit, which detects the force directed opposite to the feed force, is arranged directly inside the extruder between the feed unit and the extruder nozzle. Thus, the feed force and consequently the feed speed of the base material and the melted application material can be corrected and regulated directly and promptly during extrusion. Because the force absorption unit is integrated directly within the device, the size of the extruder is not increased or only increased slightly. In addition, the force absorption unit can be arranged in such a way that mobility of the extruder nozzle and/or a print head in the installation space is not hindered and/or restricted during application.

The device thus enables an optimal additive manufacturing process using a directly controllable extruder nozzle. As a result, additive manufacturing and plastic processing, particularly of plastics, are being improved.

By measuring the force on the extruder using the force absorption unit in conjunction with an intelligent control circuit of the control device, the quality of the melt layer application, for example on a construction platform, can be measured and/or improved. This means that productivity can be increased using the device and a corresponding 3D printer can be designed as an Industry 4.0 component.

The extruder nozzle usually has a smaller cross section than the solid base material (filament) and the base material is converted into the molten application material with a liquid to pasty viscosity by means of the heating unit. For this purpose, a feed force is usually required to advance the base material towards the extruder nozzle and to push the melted application material through the extruder nozzle. Here, the feed unit is subjected to a force opposite to the feed force, which is necessary to push the melted application material through the extruder nozzle. The force absorption unit is integrated into the device (extruder) in such a way that this oppositely directed force is detected between the extruder nozzle and the feed unit. The force measurement using the force absorption unit thus provides an alternative to pressure measurement in an extrusion device.

An essential idea of the invention is based on the fact that a force absorption unit is arranged directly between the feed unit and the extruder nozzle of an extrusion device, in particular directly between the feed unit and the thermal barrier, which is usually located in front of the heating unit for separating the feed unit and heating unit, and by means of the force absorption unit The force directed opposite to the feed force is detected and used in a closed control loop by the control device to regulate the feed speed of the feed unit, and a constant flow of application material can therefore be set directly and promptly.

The following terms are explained:

A “device” (also called an “extrusion device” or “extruder”) is in particular a device for melting and extruding a base material. In the device, a particularly solid base material is advanced towards the extruder nozzle by means of a feed unit and the base material is melted into the molten application material during the advance by means of a heating unit, the molten application material being extruded through the extruder nozzle.

A “base material” (also called starting material) is in particular a solid material that is melted and extruded in the melted state as an application material. A base material includes in particular plastic, synthetic resin, ceramic, glass and/or metal and/or metal alloy. A base material can also include carbon and/or graphite material. In addition, a base material can also have carbon, graphite and/or glass fibers.

“Extruding” is understood to mean, in particular, pressing the molten, viscous application material through the extruder nozzle.

A “melt layer application” is understood to mean, in particular, a layer-by-layer application of melted, extruded application material using the device onto a construction and/or workpiece platform. When applying a melt layer, a body and/or component is usually built up by the 3D printing head repeatedly moving over a working plane line by line and stacking the working plane upwards, so that a shape of the body and/or component is created in layers.

“Melting” is understood in particular to mean a phase transition of a solid base material into the pasty or liquid state of aggregation, so that a molten application material (molten base material) is present. The melting takes place in particular while the base material is being advanced towards the extruder nozzle by means of the heating unit. A “heating unit” (also called “hot end”) is in particular a heating element with which heat is supplied to the base material. A heating element can in particular be an electrical and/or inductive heating element. A heating element can also be a heating element operated with a heat transfer medium, for example a heating element through which hot oil or hot water flows. The heating unit is in particular arranged in front of the extruder nozzle or integrated into it, so that a heated extruder nozzle is present. By means of the heating unit, the base material is melted into the molten application material, in particular at a temperature in a range between 60 ° C and 450 ° C, preferably between 180 ° C and 300 ° C.

An “extruder nozzle” is in particular a technical component of the device for influencing the molten application material as it passes from a pipe flow into the free space during melt layer application. The extruder nozzle in particular shapes the viscous, melted application material. The extruder nozzle has, in particular, the same cross-sectional area over its entire length or tapers towards the extruder nozzle opening for the molten application material to emerge from the extruder nozzle. The extruder nozzle in particular has an extruder nozzle opening (outlet) with a diameter in a range from 0.2 to 0.8 mm, preferably from 0.25 to 0.4 mm. In particular, the extruder nozzle has a pressure in a range of 10 to 1,500 bar and/or a temperature of 60 °C to 300 °C.

A “feed unit”, for example, is a device of the extrusion device which conveys the solid base material towards the extruder nozzle and thus the application material melted from the base material. The feed unit in particular has a drive and/or motor. The feed unit converts in particular the rotary motor movement into a translational feed movement of the base material (filament) with a feed force.

“Feed force” is understood to mean, for example, the force of a feed movement with which the base material is continuously guided through the device from the feed unit to the extruder nozzle and thus the base material and the melted application material are moved and/or pressed through the device.

An “opposite force” is a force that is directed in the opposite direction to the feed force. Since, according to the principle of technical mechanics, the feed force is generally only as large as the opposite force as a counterforce, the feed unit in particular is subjected to an oppositely directed force, which is necessary to press the molten application material through the extruder nozzle. The force that is directed in the opposite direction to the feed force is thus detected by means of the force receiving unit and consequently also the feed force. The oppositely directed force has, in particular, a direction which is in the opposite direction to the direction of the feed force. With the force directed in the opposite direction However, it can also be a force that has any direction that deviates and/or is different from the direction of the feed force. The oppositely directed force can therefore also be, for example, a force with a direction perpendicular to the direction of the feed force.

A “force recording unit” is in particular a sensor for measuring a force. The force absorption unit measures in particular a force which acts on the force absorption unit. A force recording unit can in particular also be a force sensor, a force transducer and/or a load cell. The force recording unit measures in particular an elastic deformation, whereby tensile and/or compressive forces can be measured. In particular, a strain and/or expansion force is also detected by means of the force absorption unit. A force recording unit is, for example, a piezoelectric force sensor, a strain sensor and/or a transducer based on a strain gauge.

A “control device” is in particular a device that feeds back a measured value and sets a control value. By means of the control device, a controlled variable is either kept as constant as possible (fixed value control) or influenced in such a way that it follows a predetermined time change (sequence control), even when a disturbance occurs. The control device uses in particular the oppositely directed force measured by the force absorption unit and compares this with a selected reference variable. Due to the control deviation determined in the control device, the feed force of the feed unit and thus the feed speed are adjusted so that in particular there is a constant flow of application material. The control device in particular has a closed control loop in order to actively intervene in the feed of the extrusion device and to actively regulate the extrusion processes. The control device is in particular arranged in the housing of the device or the control device is assigned externally to the device and both are connected to one another at least in terms of data technology. The control device has in particular a computer and/or a microcontroller.

In a further embodiment, the feed unit has a stepper motor, wherein the stepper motor can be regulated by means of the control device based on the detected oppositely directed force.

Thus, to operate the feed unit, the rotary movement is realized by means of a stepper motor, which can be positioned precisely and has an optimal response to changes in speed as well as to starting and stopping when starting and stopping. This enables precise reproducibility of the feed movement and ensures that the control device is able to adapt the speed of the stepper motor to the specified feed force during operation. Consequently, the force recording unit provides the necessary parameters for measuring the force directed in the opposite direction and thus proportional to the feed force to regulate the speed of the stepper motor. It is particularly advantageous here that the feed is generated precisely using the stepper motor as a drive.

A “stepper motor” is in particular a synchronous motor in which the rotor, as a rotatable motor part of the shaft, can be rotated by a small angle (step) or its multiple as a non-rotatable motor part by a controlled, step-by-step rotating electromagnetic field of the stator coils. A stepper motor can in particular also be a linear motor.

In order to measure the oppositely directed force precisely on and/or in the area of the solid base material moving due to the feed, the force absorption unit is arranged between the feed unit and the heating unit.

Consequently, the force is determined in particular on the moving solid filament or assigned to the moving solid filament before it is melted into the application material.

According to the invention, the device has a rigid holding unit, with the extruder nozzle being arranged on the rigid holder nozzle.

By firmly holding the extruder nozzle on the rigid holding unit, a high level of positional accuracy of the extruder nozzle is ensured, which is necessary for a high-quality extrusion process.

A “rigid holding unit” is understood to mean, in particular, a connecting element which holds the extruder nozzle in a certain position, the holding unit itself being rigid and therefore not deformable and not elastic.

In order to form a bending beam, the device has a resilient lever arm, the feed unit being arranged on the resilient lever arm and the resilient lever arm being connected to the rigid holding unit.

A “resilient lever arm” is in particular a beam or lever that is attached to one side and to which force is applied on the opposite side. The feed unit is thus resiliently mounted via the resilient lever arm and due to the feed force and the opposing force that occurs as a result, the resilient lever arm is subjected to an expansion and/or bending, which is detected by means of the force absorbing unit.

According to the invention, the force absorption unit is arranged on the resilient lever arm.

Thus, a bending beam is formed for force measurement, with a strain gauge or a plurality of strain gauges being arranged on the resilient lever arm, for example as a force sensor. Here, the feed unit is moved elastically in the vertical direction due to the resilient mounting on the lever arm and as a result of the feed force of the feed unit and the corresponding action of the oppositely directed force, the lever arm is bent elastically. This changes the strain of the strain gauges attached, for example, along the top and/or bottom. Consequently, a highly accurate measurement of the force is made possible.

When designed as a bending beam, the solid base material (filament) is pushed between the output of the feed unit and the input of the thermal barrier and/or the heating unit, in particular through a free space which is formed between the resilient lever arm and the rigid holding unit connected to it.

In the free space between the underside of the resilient lever arm and the rigid holding unit and thus between the underside of the feed unit and the top of a thermal barrier and/or the heating unit, the filament can also be protected by a surrounding hose, the hose preferably being flexible and/or is stretchy. This flexible and/or stretchable hose is arranged in the free space between the resilient lever arm and the rigid holding unit in particular in such a way that it does not absorb the feed force. For this purpose, the flexible and/or stretchable hose can, for example, only rest on the top of the rigid holding unit, while it does not touch the underside of the resilient lever arm and consequently does not influence the force measurement on the resilient lever arm.

In order to enable optimal feeding, advancing and melting of the base material in the device, the base material has a thermoplastic material in the form of a filament.

A “thermoplastic material” is in particular a plastic that can be thermoplastically deformed in a certain temperature range. This deformation process is reversible, so that it can be repeated as often as desired by cooling and reheating until it reaches the molten state. A thermoplastic material is in particular a molding wax or a thermoplastic, such as polyethylene, polypropylene, polylactide, ABS and/or a thermoplastic elastomer.

A “filament” is in particular a printing filament. A filament is in particular a single fiber or fibers of any length. A filament can also be a wire. A filament in particular has a diameter in a range from 0.5 to 5.0 mm, preferably from 1.75 to 3.0 mm.

In a further embodiment, the device is designed as a direct extruder or as a Bowden extruder.

This means that different types of extruders with an optimal melt layer application can be implemented using the device.

In a “direct extruder”, the feed unit and therefore the stepper motor that feeds the filament is located directly on the print head and therefore on the extruder nozzle. In contrast, with the “Bowden extruder”, the feed unit and thus the stepper motor are placed at a predetermined distance from the print head and thus the extruder nozzle, which minimizes the weight on the mechanics of the print head and avoids vibrations. The filament is usually guided from the feed unit through a long, flexible PTFE hose to the hot end (heated extruder nozzle).

In a further aspect of the invention, the object is achieved by a printer for 3D printing by means of melt layer application on a construction platform, the printer having at least one previously described device for melting and extruding a base material for a melt layer application.

This provides a self-regulating printer for 3D printing, in which a material jam of the melted application material is avoided and an optimal melt layer application on the build platform is ensured. This increases productivity using the printer, particularly in the industrial sector, and provides an Industry 4.0 component. Consequently, with this printer, due to the extruder force measurement Solution in conjunction with the intelligent control circuit of the control device records the quality of the printing performance and uses it optimally.

• - Vorschieben eines Grundmaterials in der Extrudiervorrichtung mittels der Vorschubeinheit mit einer Vorschubkraft,
• - Schmelzen des Grundmaterials zu einem geschmolzenen Auftragsmaterial mittels der Heizeinheit,
• - Extrudieren des geschmolzenen Auftragsmaterials durch die Extruderdüse für einen Schmelzschichtauftrag,
• - Erfassen einer zu der Vorschubkraft entgegengesetzt gerichteten Kraft mittels der Kraftaufnahmeeinheit während des Vorschiebens und Extrudierens, und
• - Regeln einer Vorschubgeschwindigkeit der Vorschubeinheit aufgrund der erfassten entgegengesetzt gerichteten Kraft mittels der Regeleinrichtung derart, dass ein konstanter Auftragsmaterialfluss einstellbar ist.

In an additional aspect of the invention, the object is achieved by a method for regulating an application material flow of an extrusion device, wherein the extrusion device has a feed unit, a heating unit, an extruder nozzle and a force absorption unit, and the extrusion device has a control device or the extrusion device is assigned a control device, with the following steps:

• - advancing a base material in the extrusion device by means of the feed unit with a feed force,
• - Melting the base material into a melted application material using the heating unit,
• - extruding the melted application material through the extruder nozzle for a melt layer application,
• - Detecting a force directed opposite to the feed force by means of the force absorption unit during the feed and extrusion, and
• - Regulating a feed speed of the feed unit based on the detected oppositely directed force by means of the control device in such a way that a constant flow of application material can be set.

The method enables intelligent control of the feed in an extrusion device in an additive manufacturing process using the extruder force to provide a constant material flow. The method uses in particular an extrusion device, whereby the extrusion device can be a previously described device for melting and extruding a base material for a melt layer application.

• 1 eine stark schematische Schnittdarstellung eines Extruders mit einem Kraftsensor angeordnet zwischen einer Vorschubeinheit und einer thermischen Barriere,
• 2 eine Alternative eines Extruders mit einem Biegebalken und einem starren Halter, und
• 3 die Darstellung eines geschlossenen Regelkreises zum Regeln einer Ist-Extrusionsmenge.

The invention is explained in more detail using exemplary embodiments. Show it

• 1 a highly schematic sectional view of an extruder with a force sensor arranged between a feed unit and a thermal barrier,
• 2 an alternative of an extruder with a bending beam and a rigid holder, and
• 3 the representation of a closed control loop for regulating an actual extrusion quantity.

An extruder 101 has a feed unit 103 with a stepper motor 105. A control device 117 is arranged on the feed unit, which is connected externally by means of a power and data cable (see 1 ). A force sensor 107 followed by a thermal barrier 109 is arranged on an underside of the feed unit 103. On the underside of the thermal barrier 109 there is a heating element 111 and an extruder nozzle 113. Below the extruder 101 there is a platform 115 for applying a melt layer.

The extruder 101 has a continuous free space from an upper side of the feed unit 103 to an outlet of the extruder nozzle 113, through which a filament 119 is guided. The filament 119 has a diameter of 3 mm. In contrast, the outlet of the extruder nozzle 113 has a diameter of 0.25 mm.

The following work processes are carried out with the extruder 101:

The filament 119 is continuously conveyed by the feed unit 103 driven by the stepper motor 105 through the clearance through the force sensor 107, the thermal barrier 109, the heating element 111 and the extruder nozzle 113. Here, the thermal barrier 109 serves to thermally separate the hot heating element 111 from the previously arranged feed unit 103. By means of the heating element 111, the filament, which has polylactides, is heated to a temperature of 200 ° C, whereby it changes into a melted, pasty state. The melted filament is pressed through the extruder nozzle 113 at high pressure and applied to the platform 115 as a melted application material 121 as a melt layer application.

During the continuous feed of the filament 119, a force directed opposite to the feed force is continuously measured by means of the force sensor 107, which occurs due to the different diameters of the filament and the outlet of the extruder nozzle 113 as well as a narrowing of the diameter in the extruder nozzle 113. The force measurement values determined by the force sensor 107 are transmitted to the control device 117 and used to regulate the feed speed of the filament 119 by means of the feed unit in such a way that there is a constant application material flow of the melted application material 121.

In an alternative, an extruder 201 has a feed unit 203, which is arranged on a bending beam 223. At one of the feed unit 203 opposite end of the Bie beam 223, the bending beam 223 is attached to a rigid holder 225 by means of two screws 227 (see 2 ). Outside this fastening area, there is a free space with a distance 229 between an underside of the bending beam 223 and an upper side of the rigid holder 225.

A thermal barrier 209 followed by a heating element 211 and an extruder nozzle 213 is arranged on the side of the rigid holder 225 opposite the screws 227. There is a vertical opening for carrying out an in 2 filament, not shown, through the feed unit 203 and through the thermal barrier 209, the heating element 211 and the extruder nozzle 211 arranged flush in a vertical direction, so that the filament, not shown, by means of the feed unit 203 straight down through the free space with the distance 229 directly further in the vertical opening of the thermal barrier 209 is pushed.

A force sensor 207, which is designed as a strain gauge, is glued to the top of the bending beam 223.

With the extruder 201, the analogous work processes described above of feeding, melting and extruding the filament are carried out in an analogous manner.

The extruder nozzle 213 is held in a precise position by means of the rigid holder 225. In contrast, the feed unit 203 is resiliently mounted via the flexible bending beam 223 and moves elastically in the vertical direction. Due to a feed force of the feed unit 203 and an action of a correspondingly oppositely directed force, the bending beam 223 is subjected to an expansion which is proportional to the feed force and is detected by the force sensor 207. The force sensor 207 sends the continuously determined force measurement values to the in 2 control device 217, not shown.

For control purposes, a target extrusion quantity 231 is specified in the extruder 201 and this value is passed on to the control device 217. A motor feed is calculated in the control device 217 and used to adapt the feed 235 to the in 2 stepper motor 205, not shown (see 3 ).

Disturbances occurring during melting and extrusion, such as a diameter deviation of the filament and a minimal temperature deviation at the heating element 211, cause a change in the actual extrusion quantity 239 and are registered as changes in the measured force values and recorded as input variable 241 by the force sensor 207. These are transferred from the force sensor 207 as feedback 243 to the control device 217 for setting the required target extrusion quantity 231. A constant actual extrusion quantity 239 and thus a constant application material flow are thus set via a closed control loop using the force sensor 207 and the control device 217.

Consequently, a self-regulating extruder 201 is provided, which ensures continuous, consistent application quality and thus component quality.

Reference symbol list

101

extruder

103

Feed unit

105

stepper motor

107

Force sensor

109

Thermal barrier

111

Heating element

113

extruder nozzle

115

platform

117

Control device

119

Filament

121

melted application material

201

extruder

203

Feed unit

205

stepper motor

207

Force sensor

209

Thermal barrier

211

Heating element

213

extruder nozzle

217

Control device

223

bending beam

225

rigid holder

227

screw

229

Distance

231

Target extrusion quantity

233

Information about the control deviation

235

Feed adjustment

237

Disturbance variable

239

Actual extrusion quantity

241

Input size

243

return

Claims (7)

Device (101, 201) for melting and extruding a base material (119) for a melt layer application, the device comprising a feed unit (103, 203) for advancing the base material and a melted application material (121) with a feed force, a heating unit (111, 211 ) for melting the base material into the molten application material and an extruder nozzle (113, 213) for extruding the molten application material for the melt layer application, the device having a control device (117, 217) or the device is assigned a control device, and the device between the feed unit and the extruder nozzle (113, 213) has a force absorption unit (107, 207), characterized in that the device has a rigid holding unit (225), the extruder nozzle (113, 213) being arranged on the rigid holding unit, and the Device has a resilient lever arm (223), wherein the feed unit is arranged on the resilient lever arm, the resilient lever arm is connected to the rigid holding unit (225) and the force receiving unit is arranged on the resilient lever arm, so that a force directed opposite to the feed force by means can be detected by the force absorption unit and can be used by means of the control device to regulate a feed speed of the feed unit to set a constant application material flow. Device according to Claim 1 , characterized in that the feed unit has a stepper motor (105, 205), the stepper motor being controllable by means of the control device based on the detected oppositely directed force. Device according to Claim 1 or 2 , characterized in that the force absorption unit is arranged between the feed unit and the heating unit. Device according to one of the preceding claims, characterized in that the base material has a thermoplastic material in the form of a filament (119). Device according to one of the preceding claims, characterized in that the device is designed as a direct extruder or Bowden extruder. Printer for 3D printing by means of melt layer application on a construction platform, characterized in that the printer has at least one device (101, 201) for melting and extruding a base material for a melt layer application according to one of Claims 1 until 5 having. Method for regulating an application material flow of an extrusion device (101, 201), wherein the extrusion device has a feed unit (103, 203), a heating unit (111, 211), an extruder nozzle (113, 213), a force absorption unit (107, 207), a rigid Holding unit (225) and a resilient lever arm (223), the extruder nozzle (113, 213) being arranged on the rigid holding unit, the feed unit being arranged on the resilient lever arm, the resilient lever arm being connected to the rigid holding unit (225), the force absorption unit is arranged on the resilient lever arm and the extrusion device has a control device (117, 217) or the extrusion device is assigned a control device, with the following steps: - advancing a base material in the extrusion device by means of the feed unit with a feed force, - Melting the base material into a melted application material using the heating unit, - extruding the melted application material through the extruder nozzle for a melt layer application, - Detecting a force directed opposite to the feed force by means of the force recording unit during the feed and extrusion, and - Regulating a feed speed of the feed unit based on the detected oppositely directed force by means of the control device in such a way that a constant flow of application material can be set.

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